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Review of Fluid Structure Interaction Methods Application to Floating Wave Energy Converter
Zullah, Mohammed Asid,Lee, Young-Ho Korean Society for Fluid machinery 2018 International journal of fluid machinery and syste Vol.11 No.1
Computational fluid dynamics (CFD) is a highly efficient paradigm that is used extensively in marine renewable energy research studies and commercial applications. The CFD paradigm is ideal for simulating the complex dynamics of Fluid-Structure Interactions (FSI) and can capture all kinds of nonlinear fluid motions. While nonlinear simulations are considered more expensive and resource intensive compared to the frequency domain approaches, they are much more accurate and ideal for commercial applications. This review study presents a comprehensive overview of the computation fluid dynamics paradigm in context of wave energy converter (WEC) and highlights different CFD tools that are available today for commercial and research applications. State-of-the-art CFD codes such as ANSYS CFX that are highly ideal for WEC simulation problems are highlighted and aspects such as time and frequency domains are also thoroughly discussed along with efficacy of the nonlinear simulations compared to the linear models. The paper presents a comparative evaluation of different WEC modelling codes available today and illustrates the code framework of different CFD simulation software suites.
Performance Analysis of a savonius type direct drive turbine for wave energy conversion
Zullah, Mohammed Asid,Prasad, Deepak Divashkar,Choi, Young-Do,Lee, Young-Ho 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.06
Although oscillating water column type wave energy devices are nearing the stage of commercial exploitation, there is still much to be learnt about many facets of their hydrodynamic performance. The techniques of Computational Fluid Dynamics (CFD) are applied to simulate a wave energy conversion device in free surface such as waves. This research uses the commercially available ANSYS CFX computational fluid dynamics flow solver to model a complete oscillating water column system with savonius turbine incorporated at the rear bottom of the OWC chamber in a three dimensional numerical wave tank. The purpose of the present study is to investigate the effect of an average wave condition on the performance and internal flow of a newly developed direct drive turbine (DDT) model for wave energy conversion numerically. The effects of blade angle and front lip shape on the hydrodynamic efficiency are investigated. The results indicated that the developed models are suitable to analyze the water flow characteristics both in the chamber and in the turbine. For the turbine, the numerical results of torque were compared for the all cases. The results of the testing have also illustrated that simple changes to the front wall aperture shape can provide marked improvements in the efficiency of energy capture for OWC type devices.
Performance analysis of a 3 bladed & 5 bladed savonius rotor for wave energy conversion by CFD
Zullah, Mohammed Aisd,Prasad, Deepak,Choi, Young-Do,Lee, Young-Ho 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.06
A variety of technologies have already been developed to capture energy from the ocean waves, this one is simple to construct. Rather then looking at the surface waves, the technique used lets the waters current beneath the waves directly drive the rotors. The novel ocean wave energy convertor consists of savonius rotor which is mounted in the ocillating water column (OWC) chamber. This study investigates the performance of a 3 blade and 5 bladed savonius rotor under same wave condition using commercial CFD code. Initially the performance analysis of savonius type turbine have been carried out with conventional three bladed curved rotors. From the experieneces of the simulations, 5 bladed savonius rotor have been developed and studied. Performace caracteristics of the 5 bladed savonius rotor has been evaluated and the results obgtained are comopared with the conventional three bladed curved rotors.
Review of Fluid Structure Interaction Methods Application to Floating Wave Energy Converter
Mohammed Asid Zullah,Young-Ho Lee 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.1
Computational fluid dynamics (CFD) is a highly efficient paradigm that is used extensively in marine renewable energy research studies and commercial applications. The CFD paradigm is ideal for simulating the complex dynamics of Fluid-Structure Interactions (FSI) and can capture all kinds of nonlinear fluid motions. While nonlinear simulations are considered more expensive and resource intensive compared to the frequency domain approaches, they are much more accurate and ideal for commercial applications. This review study presents a comprehensive overview of the computation fluid dynamics paradigm in context of wave energy converter (WEC) and highlights different CFD tools that are available today for commercial and research applications. State-of-the-art CFD codes such as ANSYS CFX that are highly ideal for WEC simulation problems are highlighted and aspects such as time and frequency domains are also thoroughly discussed along with efficacy of the nonlinear simulations compared to the linear models. The paper presents a comparative evaluation of different WEC modelling codes available today and illustrates the code framework of different CFD simulation software suites.
CFD study of an airfoil for small wind turbine applications
Wata, Joji,Zullah, Mohammed Asid,Lee, Young-Ho 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.05
Small horizontal axis wind turbines (HAWTs) can be used to produce power in areas where the wind conditions are not favorable or optimal for large HAWTs. A newly designed airfoil for use in small HAWTs was analyzed in CFD to predict the aerodynamic performance at various Reynolds numbers over a various angles of attack. The coefficient of lift and drag, CL and CD, and the pressure distribution over the airfoil was obtained. It was found that the airfoil could achieve very good aerodynamic characteristics. The results of the numerical analysis will be compared against experimental data for validation purposes.
Prasad, Deepak,Zullah, Mohammed Asid,Choi, Young-Do,Lee, Young-Ho 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.06
Recent developments such as concern over global warming, depletion of fossil fuels and increase in energy demands by the increasing world population has eventually lead to mass production of electricity using renewable sources. Apart from wind and solar, ocean holds tremendous amount of untapped energy in forms such as geothermal vents, tides and waves. The current study looks at generating power using waves and the focus is on the primary energy conversion (first stage conversion) of incoming waves for two different models. Observation of flow characteristics, pressure and the velocity in the augmentation channel as well as the front guide nozzle are presented in the paper. A numerical wave tank was utilized to generate waves of desired properties and later the turbine section was integrated. The augmentation channel consisted of a front nozzle, rear nozzle and an internal fluid region representing the turbine housing. The analysis was performed using the commercial CFD code.
Primary Energy Conversion in a Direct Drive Turbine for Wave Power Generation
Prasad, Deepak Divashkar,Zullah, Mohammed Asid,Kim, You-Taek,Lee, Young-Ho 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.06
Recent developments such as concern over global warming, depletion of fossil fuels and increase in energy demands by the increasing world population has eventually lead to mass production of electricity using renewable sources. Ocean contains energy in form of thermal energy and mechanical energy: thermal energy from solar radiation and mechanical energy from the waves and tides. The current paper looks at generating power using waves. The primary objective of the present study is to maximize the primary energy conversion (first stage conversion) of the base model by making some design changes. The model entire consisted of a numerical wave tank and the turbine section. The turbine section had three components; front guide nozzle, augmentation channel and the rear chamber. The augmentation channel further consisted of a front nozzle, rear nozzle and an internal fluid region representing the turbine housing. Different front guide nozzle configuration and rear chamber design were studied. As mentioned, a numerical wave tank was utilized to generate waves of desired properties and later the turbine section was integrated. The waves in the numerical wave tank were generated by a piston type wave maker which was located at the wave tank inlet. The inlet which was modeled as a plate wall which moved sinusoidally with the general function, x=asin{omega}t. In addition to primary energy conversion, observation of flow characteristics, pressure and the velocity in the augmentation channel, rear chamber as well as the front guide nozzle are presented in the paper. The analysis was performed using the commercial code of the ANSYS-CFX. The base model recorded water power of 29.9 W. After making the changes, the best model obtained water power of 37.1 W which represents an increase of approximately 24% in water power and primary energy conversion.